Means for maintaining a substantially constant level of liquids in tanks



March 3, 1931. JOHNSON 1,794,962

MEANS FOR MAINTAINING A SUBSTANTIALLY CONSTANT LEVEL OF LIQUIDS IN TANKS Filed May 15, 1925 4 Sheets-Swat 1 In ven for:

Edward E 72 M )71 for/2 eua March 3, 1931. E JOHNSQN 1,794,962

LIQUIDS IN TANKS MEANS FOR MAINTAINING A SUBSTANTIALLY CONSTANT LEVEL OF Filed May 15, 1925 4 Sheets-Sheet 2 March 3, 1931. JOHNSON I 1,794,962

MEANS FOR MAINTAINING A SUBSTANTIALLY CONSTANT LEVEL OF LIQUIDS IN TANKS Filed May 15, 1925 4 Sheets-Sheet 5 March 3, 1931. E. E. JOHNSON 1,794,962

MEANS FOR MAINTAINING A SUBSTANTIALLY CONSTANT LEVEL OF LIQUIDS IN TANKS Filed May 15, 1925 4 Sheets-Sheet 4 :21 Jso Inventor:

. 94 Edward E J'ohnson g4 I w-l i atented 3 19% iii Application filed may 15,

My invention relates to means for mainturning a substantially constant level of liquid 1n tanks. This invention IS in the nature of an improvement on the device disclosed and claimed in Letters Patent ot' the United States l lo. 1 4563386 granted August X, 1923 to Herbert L. l Vherland. l llhile obviously adapted for other uses, it relates more particularly to devices for use in connection with water towers of water supply systems. An object is to provide a compact self-contained instrument comprising the necessary height 01 column. Another object is to provide an eliicient electrical device which will operate to start the flow of liquid from a source supply into the tank when the liquid therein falls to what is considered. the permissible minimum level and which will operate to stop the llow of liquid into the tanlr when. the desirable maximum level in the tank is reached. Another object is to provide a device of this character which can be readily adjusted or set so that the tank may be kept substantially full or may be kept at any other desired depth of liquid and which can be adjusted so that the fluctuations between maximum and minimum depths may be varied.

The full objects and advantages of my in vention will appear in connection with the detailed description thereof and the novel features embodied in my inventive idea will be particularly pointed out in the claims.

Tn the accompanying drawings which illustrate a practical embodiment of my invention in one form. 1 is an elevational view showing my invention applied to a water tower. Fig. 2 is a view in cross-section on the line E22 of Fig. 3. Fig. 3 is a vertical sectional view or the device. Fig. l is a view in horizontal section on the line H of Fig". 3. Fig. 4A is a view on an enlarged scale of a portion of l. 5 is a view in horizontal section on the line 55 of Fig. 3. Figs. 6, 7 and 8 are wiring diagrams showing certain parts moved successively into dillerent positions.

In the embodiment oi the invention chosen for illustrative purposes and referring first to l a pump 16 drawswater through 1925. Serial 1T0. 30,51

a pipe 12 from the source of supply and de livers it to a pipe 14 which is connected to the usual distribution system by pipe 15 and through a riser pipe 16 with a tank 18 mounted on supports 20 to constitute a water tower. The pipe 14: is also connected with vertical pipe 22 provided with a needle valve 24 best shown in Fig. 3 and the purpose of which will be explained later. The pipe 22 is connected with a horizontal pipe 26 which in turn is joined by an elbow connection to a T 28 from which a pipe 30 leads to a pressure gauge 32. The principle of operation underly the mechanism of VVherland in Pat. No. 1,463,986 already referred to and that involved in this application is identical: viz. the balancing of a head of water by an equivalent head of mercury. A. water head of 135 feet for example is balanced by a head of approximately 10 feet of mercury. Such heads of water and greater are commonly used and the corresponding lengths of mercury columnas in l 7herland-are unwieldy and ditlicult to set up. To overcome this obstacle and produce a compact instrument easy to install. T provide a plurality of U- tubes 35, l3 and 49 Fig. 3 of such number and such length (commonly about four feet) as will together have the aggregate capacity required in the head of mercury. These tubes are preferably of steel and are filled to about one half their height with mercury ll l to a common level such as indicated by the line M"M in Fig. 3, altho great accuracy in this respect is not necessary. The initial end 34 of the first ll-tube 35 extends somewhat above the common mercury level l /l' occuplied when the instrument is under atmospheric pressure and is connected to the water supply thru the pipe 22 as shown. The U- tube 35 terminates by branch 36 in a head-- 7 block 38 which should be made or balrelite or other suitable insulating material the necessity for which will be explained later, and to which it is secured in a liquid-tight man ner as by screw threading for example. The next ll-tube 43 in the series terminates in the embodiment shown with both branches 4% and 44 in the headblock 38. Other and similar ll-tubes not shown in this embodiment may by its initial branch 48 and by its final branch 50 in the contactor 51 which will be described later on. The headblock 38 is provided with chambers 41 and 45 connecting the adjacent branches of U-tubes and 43 and 43 and 49 respectively. Chambers 41 and '45 are open through the top of the block 38 for convenience in filling the instrument and are provided with liquid-tight caps 40 and 46. ll til-tubes 35, 43 and 49 are now filled with mercury to their halt-height M, it is evident that the pressure resisting capacity of each is measured by the maximum difierence in level obtained when the mercury is forced downward to M in the initial branch and upward to'M in the final branch. In order to avail myself of the total capacity of the series of U-tubes, l fill them above the mercury, with an insulating liquid 0 of light specific gravity preferably a mineral oil thru and including the chambers 41 and 45. It will be understood that the oilis very much lighter than the mercury and always remains at the top and the mercury cannot pass from one U-tube to another. The mercury columns for each U-tube therefore will always have their predetermined heights for any given pressure in the liquid system. The final branch 50 of U-tube 49 is joined by a union 52 to thelower end of a tube 54 of bakelite or other insulating material, the upper end of this tube being secured for convenie'nce in an opening in the headblock 38. A metal tube 56 which constitutes part of the contactor 51 is slidably mounted in the tube 54, the upper end of the tube 56 extending above the tube 54 and being secured in a socket in an insulating block 58. The tube 56 is encircled by a metal pinch band 60 shown in Fig. 4 and carried bv a bracket 62 secured to the headblock 38. The tube 56 is provided with a longitudinal slot 57 as shown in 4A to prevent the formation of an air pocket due to change in the mercury level. A wire 64 is secured to the bracket 62. A metal rod 66 is encased in a fixed covering 6'? of insulating material and this composite rod is mounted in the metal tube 56, so that it may be slid therein when released as will be explained later. The metal rod 66 at its extrem'e lower tip is preferably convex and is bare of insulating material while the upper portion ofthis rod is also bare and extends through an opening 'in the block 58 and through an opening in a metal sleeve 68 mounted in the block. The branch 50 contains only mercury which under pressure extends up into the tube 54 so that at the proper time it may make contact with the lower end of the metal tube 56 as well as with the metal rod 66.

The liquid tight caps 40 and 46 are secured in place and the Ll-tubes constitute, for operative purposes, one continuous tube, so that pressure applied to the initial branch of the U-cube-35 is resisted in part by the unbalanced mercury therein and in part by the unbalanced mercury in the U-tubes 43 and 49 to which the pressure is transmitted by the intervening pistons of oil 0, and the total load impressed on the U-tube 35 is thus distributed among and borne by all the tubes of the series. I am thus able-to provide the necessary mercurial balance for the widely varying pressures encountered in practice by varying the height and number of the U-tubes and still keep the instrument in a compact form which is convenient and prac tical to erect and operate. A screw 70 threaded into the sleeve 68 engages the rod 66 and holds it adjustably in place in the block. A wire 72 is attached to the sleeve 68, and as will be seen from Figs. 6, 7, and 8 this wire includes the coil of an electro-magnet 7 4, the outer end of the wire being connected to a contact post '16. The wire 72 is connected by a branch wire 78 with a contact post 80 which will be referred to later. The wire 64 includes the coil of an ,electro-magnet 82, the outer end of this wire being connected to a contact post 84. The wire 64 is connected by a branch wire 86 with the armature 88 of the electro-magnet 82 and is also connected by a branch wire 90 with the armature 92 of the electro-magnet 74. The metal U-tube 49 has a wire 94 connected therewith, this wire in Fig. 3 being shown connected with the branch 48 near its upper end altho it may be attached at any convenient position along this tube. The final U-tube 49 is made a part of the electrical circuits of the instrument and the U-tubes 35 and 43 are not; it is necessary therefore to insulate it from them. To do this, T make the headblock 38 of bakelite or other insulating material and as the oil 9 is a nonconductor of electricity, the insulation of the circuit including the U-tube 49 is provided for at this point. The pinch band'60 is for the same reason spaced away from the metal cap 46, and the branches 48 and 50 are held in place by insulating blocks thus completely insulating the final Ell-tube 49 from the rest of the instrument. The wire 94 joins with a wire 94 which includes the coil of an electro-magnet 96, the outer end of this latter wire being connected to a contact post 98. The wire 94 is connected by a branch wire 100 with a switch arm 102 adapted to be moved into engagement with either the contact post76 or a contact post I 104 by means of an insulative link 106 which connects the arm 102 with the armature 92. This armature when retracted en ages a contact post 108 which is connected by a branch wire 110 with the wire 72. The electro-magaresoe connected by a branch wire 116 with the wire 1G0. tracted, the outer end 118 thereof engages the post 84; This outer end is insulated from the main portion of the armature at 120 and this outer end is connected by a metal link 7 '122 with the outer end 124 of a switch arm 126 from the main portion of which this end.

is insulated at 128. When the armature 112 is attracted, the arm 126 engages the contact post/ and the'insulated end 124 engages a contact post 130 which is connected by a branch wire 132 with the wire 72. The armature 112 is connected by a wire 134 with one pole of a motor 186, the other pole of which is connected by a wire 138 with the arm 126. This motor drives the pump 10., The wire leading to the post 76 also leads through a green lamp 140 while a branch wire 142 connected to the post 104 leads through a red lamp 144. The supply wire from any suitable source of electricity is connected to apost 146 which is joined by a fuse 148 with a post 150 to which the wires 94 and 94 are secured. The wire 72 is connected to a post 152 which is joined by a fuse 154 to apost 156 to which the return wire to the electrical source is connected. If it were not for the insulation 67 which allows only the en'- t-reme lower end of the rod 66 to come into engagement with the mercury, the contact between this rod and the mercury would not he readily hrolren since the mercury would tend to stick to the side of the rod. when the level of the mercury is below the end of the rod. The provision of a restricted passageway the pipe section 22 such as produced by the proper setting of the needle valve 2 1- prevents variations of pressure in the water system rrom. causing a surging movement heing transmitted to the mercury and oil in.

the ll-tuloes. These tubes may he secured to n, 9 n the wall or a room. or to some other vertical support in any suitahle manner. As shown, I

three similar angle strips 158, 160 and 162 are secured to the support in vertical spaced relation, The headhloclz 38 is secured to the strip 151-; as shown in Fig. The middle and lower portions of the thtuhes are so cured to strips 160 and 162 respectively as shown Fig. 5 by being clamped between pairs of insulating lolocks 164 and 166. The strips 158 160 and 162 are held ogether ioy two verticalangle bars 168 wed thereto whereby the'tuhes are held together as a unit for convenient handling and installa tion. 18 rusilerring to Fig. 1, it will be understood the electro-magnets 4. and 82 and as oci sd. contacts are placed in a h 1% l the elastic-magnet '96 and associ sen ire places. '1. hon ilhese oozes c cured s en the armature 112 is at-' 174 through which the proper wires pass, and the wires connected to the motor pass throu h a tube 17 6 extending from the box 1%2.

The operation and advantages of my invention will-he apparent in connection with the foregoing description. -When the level of the. water in the tank falls m that there is not sufiicient pressure to maintain the mercury in contact with the lower end of the rod 66, the electro-magnet 74 is de-energized and its armature 92 comes into contact with the post 108 while the connected switch arm 102 comes into contact with the post 104 as shown in Fig. 6. This causes current to flow from the supply wire in the path indicated b the single feathered arrows in this figure, rom the post 150, the current flows through the wire 94 including the coil of the electro magnet 96, to the post 98, through the armature 88, wire 86, a portion of the wire 64, the wire the armature 92,;to the post .108, through the wire 110 and to the return wire connected to the post 152. Current also flows as indicated by the double feathered arrows from the post 150 through the wire 100, arm 102, post 104,.red lamp 144 andwire 72 to the return wire. The energization of the electromagnet 96 attracts its armature 112 and brings it into contact with the post 114 while the arm 126 is brought into contact with the post 80. Current now iiows as indicated by the triple feathered arrows from the wire 100 through the wire 116, to the post 114, through the armature 112., through the wire 134, the motor 136, th-e'wire 138, the arm 126, to the post 80, through the'wire 7 8 and wire ?2 to the return wire. This energizes the motor and causes it to operate the pump, VJ hen the increased pressure oi" water in the tank is suf ficient to cause the mercury to rise-slightly and engage the lower end of the rod 66, a cir cuit is completed through this rod as will be apparent from Fig. 7 and current now flows as indicated by the single feathered arrows from the post 150 through the wire 94 to the mercury in the tube 49, through the rod 66, the wire '12, including the coil of the electromagnet '54 and to the return post 152. The energization of the electro-magnet '14 attracts the armature 92 and draws it from engage ment with the post 108 and pulls the arm 102 into contact with the post 76. Current now flows as indicated by the double feathered arrows from the post 150 through the wire 100. 102 green lain-p 14.0 and wire 72 to the return post. The current continues to flow as indicated hy the triple feathered an rows the-wire 116v to the post 114. through the armature 12, the wire 134, the motor, the 138 the arm 125$; and the wire and return post 152., L "r eiectro-rnagnet 96 now s hy the quad,-

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including the electro-magnet 96 to the post 98, through the armature 88, the wire 86, the wire 64, to the post 84, through the link 122 to the post 130, through the wire 132 to the wire 72 and the return post 152. When the mercury rises to the bottom of the tube 56 as shown in Fig. 8, a circuit is completed through this tube and current at'first flows as indicated by the single feathered arrows through the wire 64 including the coil of the electro-magnet 82 to the post 84, through the link 122, to the post 130 and through the wire 72 to the return post. Energization of the electro-magnet 82 attracts its armature 88 and breaks connection with the post 98 so that the circuit through the 'electro-magnet 96 is broken, and the armature 112 retracts thereby moving it from contact with the post 114;' and causing the arm 126 to move from contact with the post 86 so that the circuit through the motor is broken and the pump stops. It will be. understood that this action takes place almost instantaneously. Current continues toflow-as indicated by the double feathered arrows; in this figure through the wire 100, the arm 102, the green lamp 140 and wire 7 2 to the return post. Current also,

flows as indicated by the triple feathered arrows from the rod 66 through the wire 7 2 including the coil of the electro-magnet 74 and to the return post 152. This maintains the armature 92 in the engagement with the electro-magnet 74: until the level of the water in the tank falls suficiently to permit the mercury to drop below the lower end of the rod 66 whereupon the cycle of operations previously described is repeated. lt will be understood from Fig. 6 that as soon as the mercury lowers sufiiciently to break contact with the lower end of the rod 66, the red light comes on but goes ofi" almost immediately when the pumpstarts and causes the increased pressure of water to again bring the mercury into contact with the rod 66. H for any reason the pump fails to work and raise the level in the tank, the red light will stay on and indicate that something is wrong. At other times, the

green light is on which indicates that the systemis functioning properly. By referring to Fig; 3, it will be understood that when the pinch band 60 is loosened, the rod 66 together with the metal tube 56 may be raised and lowered which will result in varying the level at which the water in the tank is maintained. Also by loosening the screw 70, the rod 66 may beraised and lowered relatively to the tube 56 whereby the range between maximum and minimum depths of water in the tank may be varied.

lclaim:

1'. In a device of the class described, the combination of a tube containing mercury subjected to the pressure of a liquid, a contact rod extending into said tube and covered with a fixed layer of insulating material with meaeee the extreme lower end of the rod left bare, a tubular contact member extending into said tube around said insulating layer, connections with one of said cont-act members which cause the current to flow when the pressure of the liquid falls to a predetermined amount, and connections with the other of said-contact members which cause, current to be cut oil when the pressure of the liquid rises to a predetermined amount.

2. In a device of the class described, the combination or" a tube containing mercury subjected to the pressure of a liquid, said tube having a lower metallic portion and an upper portion of insulating material, a contact rod extending into said insulating portion and stopping short of said metallic portion, said contact rod being covered with a layer of insulating material with the extreme lowerend of the rod left bare, a tubular contact member filling the space betwee'n said insulating. layer and said insulating portion of the tube and of less length than said rod, connections with said rod which cause current to flow when the pressure of the liquid falls to a predetermined amount, and connections with said tubular member which cause current to be cut ofi when the pressure of the liquid rises to a pre-determined amount.

3. In a device for maintaining a substantially constant level of liquids, the combination of a system or substantially parallel vertical tubular members containing mercury and connected with each other at the bottom and having the intermediate members connected with each other at the top, a connection with one oi the outside members whereby the liquid whose level is to be maintained constant, and two electrical contacts in the other of the outside members throughwhich an electrical circuit is completed by the rise of mercury iasaid last mentioned member.

6%. In a device for maintaining a substantially constant level of liquids, the combination of a. system of substantially parallel vertical tubular members containing mercury and connected with each other at the top, a connection with one of the outside-members whereby the mercury is subjected to the pressure oil the liquid whose level is to be maintained constant, means for restricting the passage through said connection to prevent surging of said liquid, and two electrical contacts in the other of the outside members through which an electrical circuit is com pleted by the rise of mercury in said last mentioned member,

5. In a device tor-maintaining a substantially constant level of liquids, the combina; tion oi a plurality o1? ll-tubes bontaining mercury and connected with each other in series at theirupper ends, a connection with one of the outside branches of said tubes.- whereby the mercury is subjected to the sure of the liquid whose level is to be maintained constant, and two electrical contacts in the other of the outside branches of said tubes through which an electrical circuit is completed by the rise of mercury in said last mentioned branch.

In testimony whereof I hereunto afiix my signature.

EDWARD E. JOHNSON. 

